Replication Data for: Bread before guns or butter: Introducing Surplus Domestic Product (SDP)

Scholars systematically mismeasure power-resources and military burdens by using GDP (Gross Domestic Product) as a proxy for the income states can devote to arming. The core problem is that GDP confounds two conceptually distinct forms of income into one additive indicator. Subsistence income represents resources needed to provide the “bread” necessary to cover the basic subsistence needs of the population. Surplus income represents the remaining resources that could be allocated to “guns” or “butter.” Our new measure of SDP (Surplus Domestic Product) corrects for this measurement error by decomposing subsistence income and surplus income from total GDP. Validation exercises demonstrate that SDP outperforms GDP at measuring the distribution of power-resources. Though theoretically, we expect states’ decisions to arm is influenced by the distribution of power, empirical models using GDP find mixed support for this expectation. Strikingly, using SDP reveals strong support for this proposition.

学界常以国内生产总值（Gross Domestic Product，GDP）作为国家可投入军备建设的收入代理指标，系统性地误测了权力资源与军事负担。其核心缺陷在于，GDP将两种概念上截然不同的收入形式混同为单一加总指标：生存性收入指用于保障民众基本生存需求的“口粮”类资源，剩余收入则是可被分配至“军备”或“民用开支”的剩余资源。本文提出的剩余国内生产总值（Surplus Domestic Product，SDP）测算指标，通过将总GDP拆解为生存性收入与剩余收入两部分，修正了这一测算偏差。验证实验表明，在测度权力资源分布方面，SDP的表现优于GDP。尽管理论上我们预期国家的军备决策会受到权力分布的影响，但使用GDP作为代理指标的实证模型仅得到了混杂不一的验证结果。令人意外的是，采用SDP进行测算则能得到对该理论命题的强有力支持。